class _Promise{
  const PENDING = 'pending'
  const FULFILLED = 'fullfilled'
  const REJECTED = 'rejected'
  constructor(exector){
    this.value = ''
    this.status = PENDING
    this.callbacks = []
      exector(this.resolve.bind(this),this.reject.bind(this))
  }
  resolve(value){
    if(this.status=== _Promise.PENDING){
      this.status = _Promise.FULFILLED
      this.value = value

    }
    return this;
  }
  reject() {}
  then(){}
}